The Spring Creators Update for Windows 10 was supposed to have started rolling out to PCs last week, but a last minute "block bug" discovery gave Microsoft the willies, and it decided to delay its release. Now we know exactly why. While there were no details about the bug at the time, Microsoft stated in a blog post this week that more Windows Insiders than usual had been experiencing blue screen of death (BSOD) errors with what would have been the finalized build.

"As Build 17133 progressed through the rings, we discovered some reliability issues we wanted to fix. In certain cases, these reliability issues could have led to a higher percentage of (BSOD) on PCs for example," Microsoft said.

Microsoft contemplated releasing a followup cumulative update package to address the issue, but ultimately decided it was in everyone's best interest to hold back the Spring Creators Update's release long enough to clean up buggy code that has been affecting some systems. As part of that, the company is pushing out a new preview build (17134) to Windows Insider in the Fast ring.

"This just reinforces that Windows Insiders are critical to helping us find and fix issues before releasing feature updates to all our customers so thank you!," Microsoft added.

Presumably the new build is now the finalized version of the Spring Creators Update. If that is the case, it will begin rolling out to customers once testing is finished on the Fast ring and then the Slow ring, the latter of which is reserved for more stable releases. It might also debut under a different name—while "Spring Creators Update" has been thrown around multiple times, it was never officially announced.

Whatever it ends up being called, the new update will introduce a host of changes and improvements, including further integration of Microsoft's Fluent Design language, additional password recovery options, the ability to mute tabs in the Edge browser, and more.